1. Description of the Prior Art
The present invention relates in general to door lock devices, and more particularly to automotive door lock devices of a type which exhibits a high durability against a marked shock produced when an associated motor vehicle is encounters a vehicle collision or the like.
2. Description of the Prior Art
In conventional automotive door lock devices, there is a type which comprises a metal cover plate which has a striker receiving recess into which a striker (more specifically, a striker proper part of the striker) is insertable, a latch plate which is pivotally connected to the cover plate and detachably engageable at its leg portion with the striker, and a locking plate which is pivotally connected to the cover plate and engageable at its pawl portion with the latch plate to suppress return pivoting of the latch plate.
Usually, the door lock device is mounted to a door of a vehicle and the striker is fixed to a body of the vehicle. Upon closing of the door, the leg portion of the latch plate is brought into engagement with the striker and the pawl portion of the locking plate is brought into abutment with the latch plate to suppress a return pivoting of the latch.
When the vehicle encounters a vehicle collision or the like, a certain impact force is suddenly applied to the door lock device in not only a direction in which the door becomes opened (that is, a direction in which the striker proper of the striker escapes from the striker receiving recess) but also a fore-and-aft direction of the vehicle (that is, a direction of the axis of the striker proper of the striker).
Thus, when the impact force applied is too great, it tends to occur that not only the latch plate but also the cover plate and locking plate are largely deformed.
In order to solve this drawback, some of the conventional door lock devices employ thicker materials for such parts.
However, as is easily understood, usage of such thicker materials for the parts causes a bulky, heavy and costly construction of door lock device.